All/most/many gestures you make in NetBeans IDE are recorded in an XML file in your user directory, "var/log/uigestures", which is what makes the Key Promoter I outlined yesterday possible. The idea behind it is for analysis to be made possible, when you periodically pass the gestures data back to the NetBeans team. See http://statistics.netbeans.org for details.
Since the gestures in the 'uigestures' file are identifiable by distinct loggers and other parameters, there's no end to the interesting things that one is able to do with it. While the NetBeans team can see which gestures are done most frequently, e.g., which kinds of projects are created most often, thus helping in prioritizing new features and bugs, etc, you as the user can, depending on who and how the initiative is taken, directly benefit from your collected data, too.
Tim Boudreau, in a recent article, mentioned the usefulness of hippie completion. So, imagine that whenever you use code completion, a tip were to appear reminding you about hippie completion. And then you'd be able to choose whether you'd like to see the tip again or not, etc, i.e., customize the frequency of tips and the types of tips you'd like to be shown.
And then, it could be taken a step further. The tip plugin could be set up in such a way that anyone would be able to register new tips per gesture. For example, maybe you have something very interesting to share about code completion in NetBeans. So, you'd create your own plugin in which there'd be an HTML file containing the text you'd like to have displayed whenever you (or your team members, or your students, maybe?) use code completion. Then you'd register that HTML file in plugin's layer file, in a subfolder dedicated to the specific gesture that you're interested in commenting on.
The same is true, not just for NetBeans IDE, but for anyone creating their applications on top of the NetBeans Platform, of course.